McCrea, Bridget
[American Management Association;, ], 2005
eBooks
Becker, Norman
McGraw-Hill, 2011
Buku Teks SO
Sudjic, Deyan
Mitchell Beazley, 1986
Buku Referensi
Budworth, Geoffrey
Chancellor Press , 1997
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Maxwell-Hudson, Clare
Dorling Kindersley, 1988
Buku Referensi